org.argeo.util/src/org/argeo/util/LangUtils.java

   1 package org.argeo.util;
   2
   3 import java.io.IOException;
   4 import java.io.InputStream;
   5 import java.io.OutputStream;
   6 import java.io.Writer;
   7 import java.nio.file.Files;
   8 import java.nio.file.Path;
   9 import java.nio.file.StandardOpenOption;
  10 import java.time.ZonedDateTime;
  11 import java.time.temporal.ChronoUnit;
  12 import java.time.temporal.Temporal;
  13 import java.util.ArrayList;
  14 import java.util.Collection;
  15 import java.util.Dictionary;
  16 import java.util.Enumeration;
  17 import java.util.HashMap;
  18 import java.util.Hashtable;
  19 import java.util.Iterator;
  20 import java.util.List;
  21 import java.util.Map;
  22 import java.util.Properties;
  23
  24 import javax.naming.InvalidNameException;
  25 import javax.naming.ldap.LdapName;
  26
  27 /** Utilities around Java basic features. */
  28 public class LangUtils {
  29         /*
  30          * NON-API OSGi
  31          */
  32         /**
  33          * Returns an array with the names of the provided classes. Useful when
  34          * registering services with multiple interfaces in OSGi.
  35          */
  36         public static String[] names(Class<?>... clzz) {
  37                 String[] res = new String[clzz.length];
  38                 for (int i = 0; i < clzz.length; i++)
  39                         res[i] = clzz[i].getName();
  40                 return res;
  41         }
  42
  43 //      /*
  44 //       * MAP
  45 //       */
  46 //      /**
  47 //       * Creates a new {@link Map} with one key-value pair. Key should not be null,
  48 //       * but if the value is null, it returns an empty {@link Map}.
  49 //       *
  50 //       * @deprecated Use {@link Collections#singletonMap(Object, Object)} instead.
  51 //       */
  52 //      @Deprecated
  53 //      public static Map<String, Object> map(String key, Object value) {
  54 //              assert key != null;
  55 //              HashMap<String, Object> props = new HashMap<>();
  56 //              if (value != null)
  57 //                      props.put(key, value);
  58 //              return props;
  59 //      }
  60
  61         /*
  62          * DICTIONARY
  63          */
  64
  65         /**
  66          * Creates a new {@link Dictionary} with one key-value pair. Key should not be
  67          * null, but if the value is null, it returns an empty {@link Dictionary}.
  68          */
  69         public static Dictionary<String, Object> dict(String key, Object value) {
  70                 assert key != null;
  71                 Hashtable<String, Object> props = new Hashtable<>();
  72                 if (value != null)
  73                         props.put(key, value);
  74                 return props;
  75         }
  76
  77         /** @deprecated Use {@link #dict(String, Object)} instead. */
  78         @Deprecated
  79         public static Dictionary<String, Object> dico(String key, Object value) {
  80                 return dict(key, value);
  81         }
  82
  83         /** Converts a {@link Dictionary} to a {@link Map} of strings. */
  84         public static Map<String, String> dictToStringMap(Dictionary<String, ?> properties) {
  85                 if (properties == null) {
  86                         return null;
  87                 }
  88                 Map<String, String> res = new HashMap<>(properties.size());
  89                 Enumeration<String> keys = properties.keys();
  90                 while (keys.hasMoreElements()) {
  91                         String key = keys.nextElement();
  92                         res.put(key, properties.get(key).toString());
  93                 }
  94                 return res;
  95         }
  96
  97         /** Converts a {@link Dictionary} to a {@link Map}. */
  98         public static Map<String, Object> dictToMap(Dictionary<String, ?> properties) {
  99                 if (properties == null) {
 100                         return null;
 101                 }
 102                 Map<String, Object> res = new HashMap<>(properties.size());
 103                 Enumeration<String> keys = properties.keys();
 104                 while (keys.hasMoreElements()) {
 105                         String key = keys.nextElement();
 106                         res.put(key, properties.get(key));
 107                 }
 108                 return res;
 109         }
 110
 111         /**
 112          * Get a string property from this map, expecting to find it, or
 113          * <code>null</code> if not found.
 114          */
 115         public static String get(Map<String, ?> map, String key) {
 116                 Object res = map.get(key);
 117                 if (res == null)
 118                         return null;
 119                 return res.toString();
 120         }
 121
 122         /**
 123          * Get a string property from this map, expecting to find it.
 124          *
 125          * @throws IllegalArgumentException if the key was not found
 126          */
 127         public static String getNotNull(Map<String, ?> map, String key) {
 128                 Object res = map.get(key);
 129                 if (res == null)
 130                         throw new IllegalArgumentException("Map " + map + " should contain key " + key);
 131                 return res.toString();
 132         }
 133
 134         /**
 135          * Wraps the keys of the provided {@link Dictionary} as an {@link Iterable}.
 136          */
 137         public static Iterable<String> keys(Dictionary<String, ?> props) {
 138                 assert props != null;
 139                 return new DictionaryKeys(props);
 140         }
 141
 142         static String toJson(Dictionary<String, ?> props) {
 143                 return toJson(props, false);
 144         }
 145
 146         static String toJson(Dictionary<String, ?> props, boolean pretty) {
 147                 StringBuilder sb = new StringBuilder();
 148                 sb.append('{');
 149                 if (pretty)
 150                         sb.append('\n');
 151                 Enumeration<String> keys = props.keys();
 152                 while (keys.hasMoreElements()) {
 153                         String key = keys.nextElement();
 154                         if (pretty)
 155                                 sb.append(' ');
 156                         sb.append('\"').append(key).append('\"');
 157                         if (pretty)
 158                                 sb.append(" : ");
 159                         else
 160                                 sb.append(':');
 161                         sb.append('\"').append(props.get(key)).append('\"');
 162                         if (keys.hasMoreElements())
 163                                 sb.append(", ");
 164                         if (pretty)
 165                                 sb.append('\n');
 166                 }
 167                 sb.append('}');
 168                 return sb.toString();
 169         }
 170
 171         static void storeAsProperties(Dictionary<String, Object> props, Path path) throws IOException {
 172                 if (props == null)
 173                         throw new IllegalArgumentException("Props cannot be null");
 174                 Properties toStore = new Properties();
 175                 for (Enumeration<String> keys = props.keys(); keys.hasMoreElements();) {
 176                         String key = keys.nextElement();
 177                         toStore.setProperty(key, props.get(key).toString());
 178                 }
 179                 try (OutputStream out = Files.newOutputStream(path)) {
 180                         toStore.store(out, null);
 181                 }
 182         }
 183
 184         static void appendAsLdif(String dnBase, String dnKey, Dictionary<String, Object> props, Path path)
 185                         throws IOException {
 186                 if (props == null)
 187                         throw new IllegalArgumentException("Props cannot be null");
 188                 Object dnValue = props.get(dnKey);
 189                 String dnStr = dnKey + '=' + dnValue + ',' + dnBase;
 190                 LdapName dn;
 191                 try {
 192                         dn = new LdapName(dnStr);
 193                 } catch (InvalidNameException e) {
 194                         throw new IllegalArgumentException("Cannot interpret DN " + dnStr, e);
 195                 }
 196                 if (dnValue == null)
 197                         throw new IllegalArgumentException("DN key " + dnKey + " must have a value");
 198                 try (Writer writer = Files.newBufferedWriter(path, StandardOpenOption.APPEND, StandardOpenOption.CREATE)) {
 199                         writer.append("\ndn: ");
 200                         writer.append(dn.toString());
 201                         writer.append('\n');
 202                         for (Enumeration<String> keys = props.keys(); keys.hasMoreElements();) {
 203                                 String key = keys.nextElement();
 204                                 Object value = props.get(key);
 205                                 writer.append(key);
 206                                 writer.append(": ");
 207                                 // FIXME deal with binary and multiple values
 208                                 writer.append(value.toString());
 209                                 writer.append('\n');
 210                         }
 211                 }
 212         }
 213
 214         static Dictionary<String, Object> loadFromProperties(Path path) throws IOException {
 215                 Properties toLoad = new Properties();
 216                 try (InputStream in = Files.newInputStream(path)) {
 217                         toLoad.load(in);
 218                 }
 219                 Dictionary<String, Object> res = new Hashtable<String, Object>();
 220                 for (Object key : toLoad.keySet())
 221                         res.put(key.toString(), toLoad.get(key));
 222                 return res;
 223         }
 224
 225         /*
 226          * COLLECTIONS
 227          */
 228         /**
 229          * Convert a comma-separated separated {@link String} or a {@link String} array
 230          * to a {@link List} of {@link String}, trimming them. Useful to quickly
 231          * interpret OSGi services properties.
 232          *
 233          * @return a {@link List} containing the trimmed {@link String}s, or an empty
 234          *         {@link List} if the argument was <code>null</code>.
 235          */
 236         public static List<String> toStringList(Object value) {
 237                 List<String> values = new ArrayList<>();
 238                 if (value == null)
 239                         return values;
 240                 String[] arr;
 241                 if (value instanceof String) {
 242                         arr = ((String) value).split(",");
 243                 } else if (value instanceof String[]) {
 244                         arr = (String[]) value;
 245                 } else {
 246                         throw new IllegalArgumentException("Unsupported value type " + value.getClass());
 247                 }
 248                 for (String str : arr) {
 249                         values.add(str.trim());
 250                 }
 251                 return values;
 252         }
 253
 254         /** Size of an {@link Iterable}, optimised if it is a {@link Collection}. */
 255         public static int size(Iterable<?> iterable) {
 256                 if (iterable instanceof Collection)
 257                         return ((Collection<?>) iterable).size();
 258
 259                 int size = 0;
 260                 for (Iterator<?> it = iterable.iterator(); it.hasNext(); size++)
 261                         it.next();
 262                 return size;
 263         }
 264
 265         public static <T> T getAt(Iterable<T> iterable, int index) {
 266                 if (iterable instanceof List) {
 267                         List<T> lst = ((List<T>) iterable);
 268                         if (index >= lst.size())
 269                                 throw new IllegalArgumentException("Index " + index + " is not available (size is " + lst.size() + ")");
 270                         return lst.get(index);
 271                 }
 272                 int i = 0;
 273                 for (Iterator<T> it = iterable.iterator(); it.hasNext(); i++) {
 274                         if (i == index)
 275                                 return it.next();
 276                         else
 277                                 it.next();
 278                 }
 279                 throw new IllegalArgumentException("Index " + index + " is not available (size is " + i + ")");
 280         }
 281
 282         /*
 283          * EXCEPTIONS
 284          */
 285         /**
 286          * Chain the messages of all causes (one per line, <b>starts with a line
 287          * return</b>) without all the stack
 288          */
 289         public static String chainCausesMessages(Throwable t) {
 290                 StringBuffer buf = new StringBuffer();
 291                 chainCauseMessage(buf, t);
 292                 return buf.toString();
 293         }
 294
 295         /** Recursive chaining of messages */
 296         private static void chainCauseMessage(StringBuffer buf, Throwable t) {
 297                 buf.append('\n').append(' ').append(t.getClass().getCanonicalName()).append(": ").append(t.getMessage());
 298                 if (t.getCause() != null)
 299                         chainCauseMessage(buf, t.getCause());
 300         }
 301
 302         /*
 303          * TIME
 304          */
 305         /** Formats time elapsed since start. */
 306         public static String since(ZonedDateTime start) {
 307                 ZonedDateTime now = ZonedDateTime.now();
 308                 return duration(start, now);
 309         }
 310
 311         /** Formats a duration. */
 312         public static String duration(Temporal start, Temporal end) {
 313                 long count = ChronoUnit.DAYS.between(start, end);
 314                 if (count != 0)
 315                         return count > 1 ? count + " days" : count + " day";
 316                 count = ChronoUnit.HOURS.between(start, end);
 317                 if (count != 0)
 318                         return count > 1 ? count + " hours" : count + " hours";
 319                 count = ChronoUnit.MINUTES.between(start, end);
 320                 if (count != 0)
 321                         return count > 1 ? count + " minutes" : count + " minute";
 322                 count = ChronoUnit.SECONDS.between(start, end);
 323                 return count > 1 ? count + " seconds" : count + " second";
 324         }
 325
 326         /** Singleton constructor. */
 327         private LangUtils() {
 328
 329         }
 330
 331 }